Hi Nikola. Today is the first day I’ve looked at this thread in at least a month. I’m not sure what you’re getting at, but it’s nice to hear from you. I am meeting many young Serbs who live and work in the Washington DC area.
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Jazzguy, your principle holds if warps are always the result of local expansion or shrinkage of the vinyl disk. But you can also take a perfectly circular disk and twist it so it becomes”warped” in the horizontal plane (viewed on edge). Such a disk could be flattened and remain circular in the vertical plane ( viewed from above or below). Not sure what this has to do with entropy, but I’m all for it.
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Pindac, Please forgive me if I offended you in questioning the idea that TT bearings and their shafts commonly wear in the horizontal or lateral direction. I only meant what I actually wrote, that I have never seen it or heard from others that it is a common problem. As you may or may not know, I have a fairly extensive experience with vintage turntables, especially DD types, so my query was based on personal experience and past history with Technics, Denon, Victor, and Kenwood DD TTs. I also have extensive personal experience with Lenco and briefly with Garrard idler drive types. (Although there was nothing amiss with the spindle and bearing on my Lenco, because the Lenco was NOS, I did replace the entire assembly with a massive aftermarket spindle and bearing custom made in the UK.) I once commented on your subject by wondering out loud whether the lateral wear problem would possibly occur with a belt drive TT, where there is in fact a lateral force constantly in one direction on the spindle. I certainly do agree with you that vertical wear on the bearing and/or thrust pad is always an issue that should be addressed when one is putting any vintage or "pre-owned" TT into service. We have no disagreement there.
It would seem to me that if the spindle is wobbly in the bearing shaft, there is no solution at all except to replace the entire assembly with new.
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Pindac, You seem to have more than average problems with wobbly spindles caused by excessive wear in the bearing shaft, or your friends do. I can't recall ever having observed it.
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I see Jazz guys’ point, if you assume that a warp represents a local stretching of the vinyl, such that there is excess material in the horizontal plane and this forces the warp to occur. Like pavement expansion on hot days. If we assume that that is the genesis of a warp, then it must also be true that the LP will have thinned out in the region of the warp in order to produce the aberration. I have never observed such a thing, and I have never stored any LP ever under conditions that could conceivably cause vinyl to “melt” and warp in that fashion. So this is my reasoning why I also doubt jazz guy’s thesis. But I don’t doubt he saw what he saw. Perhaps the occasional LP comes from its factory in that condition, the warp having been caused by uneven heating in the press. But don’t we assume that most warps occur while the LP is in our own hands, in our own house?
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I recently bought a second copy of the Cardas test LP. I’ve been using it for years to warm up cartridges that either need break in or have been out of use for long periods, which happens when you own 5 turntables and 2 systems. Anyway, the new copy was very badly warped right out of the sleeve. I of course immediately returned it to MICHAEL PERCY audio, and he replaced it immediately, no questions asked. Still, it is surprising to me that Cardas could let such a thing go out the door as a test LP, of all things.
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petgo, I guess the only clue an end user would have that a cartridge is internally misaligned would be if he attempts to set azimuth electrically (equal crosstalk in each channel) and this result requires tilting the cartridge in either direction from a 90 degree orientation of the stylus tip to the groove walls. By that criterion, most cartridges are not perfect, but they are not far off, either.
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Who knew warps were so popular?
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Terry, you wrote, "My DIY air bearing tonearm / Koetsu setup is sensitive to small azimuth changes - 6 minutes of arc from perpendicular is clearly audible". That's remarkable because it infers that your Koetsu is perfectly constructed internally. If perfect 90 degrees of azimuth yields audibly superior results even in comparison to a few minutes of arc off 90 degrees, then that would be the case. There is a good case to be made for setting azimuth at 90 degrees notwithstanding electrical measurements of the results, but it usually means a slight compromise in crosstalk perfection, because most cartridges are not perfectly constructed. But your general point that warps throw off azimuth as well as speed is well taken.
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Dear jw, Your assumptions are not quite accurate. I normally do not fuss over warped LPs, as I observe them very infrequently in LPs in my collection of 2500 or more LPs, but I would not dare to guess what fraction of that total is warped. However, in the last 2-3 weeks, I observed on separate occasions that two of the LPs I selected for play on those particular days (to be clearer, one LP per listening session) were warped "severely". Especially affecting the outermost one or two tracks on each. Since I only noticed the warps when the LPs were already spinning, I was also able to observe that both LPs sounded great, were tracked well by two different high compliance cartridges (B&O MMC20CL and Ortofon MC2000 mounted in Dynavector DV505 and Triplanar, respectively), had very quiet surfaces, no ticks or pops, and great music. Because of the latter good qualities, I am loathe to discard the LPs. Normally if an LP is as warped as these two, I discard them; they usually have some other defect that justifies trashing. So I started wondering what are the latest and most cost effective methods for flattening; I would not spend the $3000 cost of the Furutech, which I already knew about, because the problem is so unusual in my personal experience. I would not make the general statement that I don’t have a problem playing warped LPs, only that these two LPs play OK.
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optimize, You make a good point and it shows good thinking, but I question whether what you say is true for all warped LPs, because in many cases the warp you observe is compensated for by several smaller less visible warps in the opposite direction. Let's call it "upward" vs "downward" warps. This is one reason why trying to get around the problem with a central clamp won't work for both sides of that LP. Thus the LP itself has not lost its basic dimensions; they are just distorted in vertical space. That should be reparable when you heat and flatten. I don't doubt your story regarding the one example.
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I think the premise behind flattening the LP by heat and pressure is the hope that the LP WILL return to its original flat shape, that the stretching represented by a warp, if it is indeed stretching, will be eliminated by a corresponding shrinkage. I must say I don't quite understand your argument that warps can never be "repaired". Anyway, when you play a warp, the warp itself does represent a longer distance between points A and B on the adjacent flat surfaces on the LP, as you say, and because the turntable motor maintains a constant angular velocity in the plane of the platter, the velocity of the stylus in the angular direction will increase momentarily between the flat points A and B, as it has to climb and descend a hill. That ought to cause a pitch change. Possibly, because this distortion occurs amidst musical passages, which are complex both in pitch and timing, perhaps that is why we may not hear a problem. The video that Mijostyn put up here on this forum, when we were discussing tonearm design clearly does show that if the LP is encoding a pure tone, e.g., 1000Hz in the case of the video about the ARXA turntable and its wonderfulness, you CAN hear the warp.
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So you’ve recently examined each and every one of your 2000 LPs, and you know for sure that only 5 have a detectable warp?
I doubt it. Actually I too had that smug attitude toward the issue, until recently I detected moderate to severe warps in 2 or 3 LPs I do not want to discard. Which led me to start this thread. But oddly and amazingly both of the LPs that were most warped actually played pretty well, and I did not detect any obvious distortion while watching the stylus trace up and down over the warp. I do not agree with Mijostyn’s hypothesis that this is because we are used to speed aberrations in the vinyl medium. I really don’t know exactly how to explain it. The stylus did not take off into the air. The tonearms were respectively my Triplanar and a Dynavector DV 505. In both cases using high compliance cartridges, so that may have something to do with the traceability.
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Thanks, guys. I think we've covered the waterfront when it comes to curing warps. Unless someone else has a treatment not already mentioned. My preference is to reduce the magnitude of the warp before playing the defective LP. I am less interested in clamps and vacuum hold down, in this instance.
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Orb from japan via eBay works for me if I decide to go that route. $1150. As noted, 100V is no problem at all. A proper step down transformer can be had for ~$50.
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edcyn baby, No vacuum hold down for me, on any of my 5 turntables. Once upon a time I did own a Star Sapphire Series III with vacuum, but no longer.
I had completely forgotten about the Vinyl Flat options, probably because warps were such a rare problem for me. Thanks for that. So far that and the Orb seem the best ways to go.
As to the Orb, they are available from a US Company; see Mijostyn’s post. 100V is no problem; just get a 120V to 100V stepdown transformer. They are cheap. I already own two of them, one for my Denon DP80 and one for my Kenwood L07D.
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audioguy, I disagree that the method you mention works well, certainly not for both sides of the same LP, because warps in one direction that may be ameliorated would not be affected as much or at all, when you flip the LP. I do have a SOTA reflex clamp, so I could give it a try for at least some of my warped LPs.
I just found the Orb too. Much less expensive than the Furutech, but still not exactly cheap. Anyway, that seems to be the best device currently available.
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